I want the privacy, sure, I don’t need some kid barging in to borrow the blow dryer when I’m looking for a little “private time.”
But then I think: “what if I have a heart attack while I’m in here? I don't want to die like Elvis.” I imagine my wife banging on the door, yelling to me through the jamb. The EMTs wasting precious time kicking down the door while I’m lying on the floor clutching my chest.
But… I lock it anyway.